Boat hull construction



Dec. l1, 1956 T. R. BRAKE 2,773,273

BOAT HULL. CONSTRUCTION Filed Jan. 16, 1953 e2" uo JNVENTOR.

United Sites Patent C BOAT HULL CONSTRUCTION Theodore R. Drake, Long Beach, Calif.

Application January 16, 1953, Serial No. 331,525

1 Claim. (Cl. 9 6) This invention relates generally to ships or boats and relates more particularly to the construction thereof.

Many diiculties are encountered in making the hulls of boats, particularly those parts which have compound curves, and because of such hull parts which have compound curves, it has been virtually impossible to use Sheet material of substantial size, such as, for example, conventional plywood sheets, in the construction or manufacture of boat hulls.

While the present invention is shown and described in connection with the use of plywood sheets, it is to be understood that other sheet material may also be used.

Ordinarily, conventional plywood sheets can be given a bend or curve in one direction but cannot be bent so as to form a compound curve.

However, I have found that by properly cutting such ordinary plywood sheets, the hull may be formed of the ,plywood pieces thus cut, such cut pieces conforming to ithe compound curves necessary in the formation of the hull and it is an object of the present invention to provide :such pieces of sheet material.

Another object of the invention is to provide such sheets which afford a great saving in time and material in the construction of boat hulls.

,Still another object of the invention is to eliminate the use of relatively narrow stripping and the moulding thereof on jigs in the construction of boat hulls.

A further object or advantage of the invention is that the hull can be formed and constructed of such cut sheet material without internal framework for reenforcing same in the completed hull.

A still further object of the invention is the formation of the hull with such sheet pieces so that it will properly strain.

Other objects and advantages of the invention will be brought out in the following part of the specification.

Referring to the drawings which are for illustrative purposes only,

Fig. l is a perspective view of a hull form with cut sheet material .embodying the present invention disposed therein;

Fig. 2 is a sectional view taken on line 2 2 of Fig. l;

Fig. 3 is a plan view of cut sheet material embodying the present invention; j

Fig. 4 is a sectional View showing a grommet for nails used in constructing the boat hull;

Fig. 5 shows an alternative splice arrangement for the sheet material;

Fig. 6 is another alternative splice arrangement for said sheet material; and

Fig. 7 is a sectional view taken on line 7--7 of Fig. 1.

Referring to Fig. l, there is shown a form, indicated generally at 1t?, on which a boat hull is constructed from sheet material embodying the present invention. The form has side portions 11 and bottom portions 12. The form has reinforcing ribs 13 and 14 on the side thereof and said form is provided with longitudinally extending :recesses for reception of the stem 16 and the keelson 17,

ICC

-Z and stringers 18 along the bottom edge of the sides 11. The stem, keelson and stringers are removably inserted in the respective recesses preparatory to the building up of the sides and bottom of the boat.

The rear portion 20 of each side of the boat curves slightly in generally one direction so that ordinary sheets of plywood or other suitable material may be used and if such sheets are of sufficient size, a single sheet may be used for the portion 20 of each side.

However, the forward portion 22 of the boat side not only curves forwardly but is bowed, as best shown in Fig. 2, so that said portion 22 contains compound curves and presents a diiicult construction problem.

i have found that by properly cutting the sheets of materials, relatively large pieces may be used so that the construction of the boat hull may be accomplished with relative rapidity, ease and saving of time and material.

In Fig.A 3, a sheet of cut sheets is shown as they appear lying fiat. The various pieces are nested and when applied to the portion 22 of the form will fit together as shown in Fig. l with the various edges properly abutted. It will be noted that the seat shown for the portion 22 comprises pieces indicated by the respective reference numerals 24, 25, 26, 27, 28 and 29. The piece 24 is shown with a large il-shaped notch 30 and a smaller notch 31 which tapers slightly outwardly from the bottom thereby providing a portion 32, a leg 33 and an intermediate leg 34. A piece 35 is received in the notch 31 and the piece 26 is received in the notch 30. The piece 26 is also provided with a notch 36 and is formed in the shape of a V having legs 37 and 38 which are joined by part 39. The piece 27 is received in the notch 36 of the piece 26 and is generally V-shaped with a notch 40, legs 41 and 42 and a joining portion 43. The piece 28 is notched at i5 and is generally V-shaped, there being legs 46 and 47, joined together by the part 48. The piece 29 is received in the notch and is roughly wedge-shaped.

The inner edges of the notches are straight and are in straight lines when applied to the hull form and, hence, are in such straight lines in the completed hull. The edges 50, 51, 52 and 53 of the piece 24 are such straight edges. The edges 55 and 56 of the piece 26 are straight edges as are the edges 57 and 58 of the piece 27 and the edges 60 and 61 of the piece 28. The bottom edge 63 of the notch 30 and the bottom edge 64 of the notch 31 are also straight `edges which run along straight lines in the hull. The bottom edge 65 of the piece 26, the bottom edge 66 of the piece 27 and the bottom edge 67 of the piece 28 are similar lines. In determining the straight lines on the hull, a straight edge, such as that of a square, is applied to the hull and turned until the straight edge of the tool contacts the hull along substantially its entire length.

The outer edge of the piece 24, which defines the outer edge of the leg 33, is so cut as to conform to the lower .edge of the hull while the edge 71 is adapted to abut against the adjacent piece on the part. 20. The edge 71 is in a transverse plane relative to the length of the hull and the surface of the sheet 24 is concave along said edge 71, as best shown in Fig. 7. The edge 72 of the piece 24 defines the upper edge of the hull. The portion 32 is readily bent to conform to the shape of the form beneath same and the same is true of the legs 33 and 34. The part 35 is readily conformable to the curvature of the form beneath it and when thus conformed, the outer edges within the notch 31 will dene straight lines and abut against the adjacent edges of said notch.

The outer edges 75 and 76 of the part 26 are curved when the piece is lying iiat but when twisted or conformed to the form 10, or that portion beneath the part 26, said edges will dene a straight line coincident with the edges S0 and 51 respectively and will abut against said edges,

3 theouter edge 77 of the piece 26 will abut against the edge 63 of the notch 30.

The outer edges 78 and 79 of the piece 27 are likewise curved when the piece is flat but when conformed to the boat structure, said edges 78 and 79 define a straight line and Will abut against the respective edges 55 and 56 of the piece 26. The end edge 80 of the piece 27 will engage the inner edge v65 of the piece 26. Likewise the outer edges 82 and 83 of the piece 28 are formed so that when conformed to the boat structure they will define a straight line and abut against the edges 57 and d8 respectively of the 'piece 27, with the edge 84 in abutment with the edge 66 of the piece 27.

The keystone shaped `piece 29 also has its outer edges 86 and 87 cut so that when the piece 29 is conformed to the boat structure, said edges 86 and 87 will engage the edges 60 and 61 of the piece 28, the edge 88 of said piece 29 then abutting the edge 67 of the piece 28.

The various pieces hereinabove described are attached to the part 22 by means of nails and the ends of the arms are cut to conform to the top edge of the hull and to the stem. The `stem is so formed that the cut edges of the adjacent plywood parts or pieces tit into a recess provided therefor.

Inasmuch as it is desirable to have more than one layer of plywood forming the hull, a second layer may be applied of sheets similarly cut, said sheets being indicated generally by the dotted Ilines in Fig. 1. lt will be noted that the top layer overlaps the edges of the bottom layer. lt is to be understood, of course, that additional lines may also b'e used if desired. Glue is used to secure the layers together land any suitable type of glue may be used such as, for example, atherma-lly setting glue. There are various known types of glue which are suitable.

The outersurface of the Vhull is covered with glass cloth to which lis applied a resin or Aliquid glass. This gives the desired surface tinishand fills in holes and the like which may be present in the sheet material.

The bottom of the boat lat the rearward end portion may-also comprise a single piece of sheet material as at 9.0 inasmuch yas the curvature is generally in one direction and is lno problem vdue to-oompound curvature. The portion ofthe "boa-t forwardly of the part 90, however, has cornpound curves land ais built up or formed of pieces of sheet material similar `to those hereinabove described. These pieces -aretgiven -thefrespective reference numerals 91, 92, 93, 94, 95, l96 and 97. These pieces are of substantial size and are Cubin-accordance with the arrangement .hereinabove described. They are also applied in the manner of thepreviouslyf described pieces. A plurality of layers are also used -for this portion of the hull Vand the same .type Vof finish or outer surfaceis used, the glass cloth and liquidglass.r Inasmuch as the nails, such as indicated at 10Q-in Fig. 4,are removedafter the glue has been dried or isset between thelsheets, :it has been foundto be advantageous to use grommets -101 on the nails so as to permit readyremoval thereof. In order to prevent marring ofthe surface of thef'plywrood sheets, a washer or pad .102 of any suitable material, such as leather, felt or the'like, is used beneath thepgrommet 101.

After the-Vgluetused in-securing the partsrof the hull together has thoroughly *.set, the hull is removed or lifted from :the form *10. lt is to-be.understood in connection with theform 10.tha't it maybe a framework or may have solid WalIs'hmIingvl the shapejdesired for the nished hull.

The formm'ay beused repeatedly andpredetermined patterns or 'templates may be made from which the pieces comprising the'hulljmay'be cut. l n preparing the patterns 'or templates for the various pieces, the form CII ill)

Cal

may be covered with paper which conforms to the outer surfaces of said form. The. straight lines along the portions of the hull having the compound curves are determined as hereinabove described and the paper is cut along said lines. When the paper is removed, the correct patterns for the vairous pieces 24 to 29 inclusive and 91 to 97 inclusive are provided.

In other Words a relatively thin and generally flat sheet of material is placed on a boat hull form and the sheet conformed to the desired compound curved surface of said form. A straight edge tool, such as a square, is adjusted along the exposed surface of the sheet until contact is made all along said surface by said straight edge, a line being then scribed on said surface along said straight edge. The tool is pivoted about a point on said line until Contact is again made all along said hull by said straight edge, a second line then being scribed along said straight edge thereby making a V-shaped mark. A similar set of lines are scribed, each parallel to and spaced from the lines forming .the V, the thin sheet of material then being cut along said lines into generally V-shaped parts.

In Figure 5 there is disclosed an alternative arrangement for joining the edges of the various pieces comprising the hull. In this arrangement, certain edges are beveled indicated at 105 and said edges are, of course, glued.

ln Fig. .6, there is shown another arrangement for joining the edges. .in this arrangement the .edge portions are cut so that when joined, they form a V .cross section and strip .1.10 is secured therein by gluing or the like. The strip 110 is generally wedge-shaped and has sides 111 and 112 which converge toa point received in the deepest por tion of the V-shaped groove, the .outer surface 113 .of said strip 110 lies in the same plane as the surfaces of the adjacent pieces of sheet material.

I claim:

In a method for making a pattern for pieces .of material for use in the construction .of a boat hull portion `having compound curved surfaces, comprising: placing a relatively thin and generally at sheet of material on a hoat hull form; conforming the sheet to the desired compound curved surface of said form; adjusting a rigid straight edge tool along the exposed surface of the sheet until contact is .made all along said surface by the straight edge; scribing .a line on .said .surface along said straight edge; pivoting said rstraight edge about apoint on said line until contact is again made all along said hull by said straight edge and scribing a second .line along said straight edge thereby making a V-shaped mark; similarly scribing a set of lines, each parallel to and spaced .from the .lines forming the V,; and cutting :the thin sheet of material along said lines ingenerally lV-shaped parts.

References Cited inthe tile of this kpatent UNITED STATES PATENTS Great Britain Oct.,22, A1940 

